Ink for transparent projection strips



Patented Sept. 12, 1939 UNITED STATES PATENT OFFICE INK FOR TRANSPARENTPROJECTION STRIPS Millard Demarest, Hackensack, and Kirtland Flynn, EastOrange, loid Corporation,

N. J., assignors to Cellua corporation of New Jersey 4 Claims.

This invention relates to transparent strips having characters printedthereon, which strips may be employed to project desired information bymeans of light upon a screen.

An object of our invention is to prepare strips made of organicderivatives of cellulose for light projection purposes which havesuperior properties to strips heretofore employed. A further object ofour invention is to prepare an ink which is eminently suitable for theprinting of characters on strips of organic derivatives of cellulose asWell as the strips made of other material heretofore used for projectionpurposes. Further objects of our invention will appear from thefollowing detailed description.

More or less transparent strips or ticker tape having stock marketquotations or other information printed thereon have been employed inlight projection machines to project such quotations upon a screen.Highly calendered paper known as glassine or foils of reconstitutedcellulose have been used for this purpose, but they have not been whollysatisfactory due to the physical or chemical properties of thesematerials.

We have found that strips made of thin foils of cellulose acetate orother organic derivative of cellulose have properties which are vastlysuperior to those of the materials heretofore employed for making stockquotation tapes that are to be employed in light projection purposes.Among the advantages of the use of cellulose acetate or other organicderivative of cellulose foil over reconstituted cellulose foil orglassine, the following are cited.

Foils made of cellulose acetate or other organic derivatives ofcellulose have a much higher transparency than that of foils made ofreconstituted cellulose so that a clearer and sharper projection, freefrom streaks, is obtained on the screen.

Foils of cellulose acetate or other organic derivatives of cellulose arematerially less aifected by changes in atmospheric conditions such ashumidity, temperature, etc. than reconstituted cellulose. Whereas stripsmade of reconstituted cellulose produce buckling, shrinking anddistortion troubles with fluctuations in room temperatures or humidity,these phenomena do not occur with foil made of cellulose acetate orother organic derivatives of cellulose. Since reconstituted cellulosefoil tends to absorb a large proportion of moisture, it tends to swelland thus bind in the projection machines where the clearance is small,and furthermore in damp weather such reconstituted cellulose foilabsorbs so much moisture that the layers thereof in the roll sticktogether rather firmly and thus interfere with unwinding. Foils ofcellulose acetate do not have these drawbacks.

Foils of cellulose acetate, being thermoplastic and soluble in certainorganic liquids, may be readily cemented together with solvents such asdiacetone alcohol, triacetin, etc. or by heat to form neat joints orsplices. Foils of reconstituted cellulose, on the other hand, are notthermoplastic and are not soluble in the usual solvents, and thereforethe splices of joints of reconstituted cellulose strips are awkward inappearance and are so bulky as to interfere with the proper feeding inthe projection machines.

Foils made of cellulose acetate or other organic derivatives ofcellulose, particularly when they contain triphenyl phosphate or otherfire retardants, are less inflammable than reconstituted cellulose orpaper, and this is a very important consideration in projectionmachines, where high temperatures due to the powerful light sourceprevail.

In the use of projection strips, ink is applied thereto with rubber orother type wetted by means of a felt wheel to which ink is applied oncea day. The printed strip or foil is immediately passed mechanicallybefore a light which projects the characters upon a screen. The ink neednot necessarily be dry before projection, and the strip or foil isrolled upon the other end of the machine. If the strip is made of paperor reconstituted cellulose, the roll, smeared with ink, cannot bereclaimed and must be discarded. On the other hand, in the case of foilsmade of cellulose acetate or other organic derivatives of ink may bewashed or bleached away and the foil reused, or the foil may beredissolved in solvents and new foil cast from the resulting solution.

Due to the superior strength of cellulose acetate foil, the celluloseacetate foil this invention may be thinner than is required ofreconstituted cellulose foil, whereby a great saving in cost iseffected.

It will therefore be seen that foils of cellulose acetate are muchsuperior to for use as projection strips.

However, we have found that the ordinary ink used in stock quotationrecording machines, which consists essentially of a mixture of MethylViolet and Methylene Blue dissolved or dispersed in glycerine to whichalcohol is added, is not absorbed smoothly and uniformly by celluloseacetate foils and therefore do not produce satisfactory markingsthereon. After a long investigation, we have discovered that an ink ormarking cellulose, the

employed in other foils or paper g fluid made of a dye or pigmentdispersed or dissolved in a liquid that is a solvent plasticizer' forthe cellulose acetate or other organic derivative of cellulose, iseminently suitable for marking not only cellulose acetate foil, but alsofor mark ing reconstituted cellulose, paper and other material.

The thin foil employed in accordance with our invention preferably ismade of an acetonesoluble cellulose acetate, but it may be made of othersuitable celulose acetates or other organic derivatives such ascellulose formate, cellulose propionate and cellulose butyrate, ethylcellulose, methyl cellulose and benzyl cellulose. Besides the organicderivative of cellulose, the foil preferably contains plasticizers forthe organic derivative of cellulose, in amounts say of to 50% of theweight of the derivative of cellulose pres- I ent, at least part ofwhich plasticizer is preferably a fire retardant such as triphenylphosphate. Examples of plasticizers for cellulose acetate are diethylphthalate, dimethyl phthalate, triacetin, a mixture of orthoandpara-ethyl toluene sulfonamid, diethyl tartrate, dibutyl tartrate, etc.

By way of example, the following composition of a foil that maybe usedin accordance with this invention is given.

Parts by weight Acetone-soluble cellulose acetate 100 Triphenylphosphate 15 Diethyl phthalate 15 To show the superior properties ofsuch cellulose acetate foils over reconstituted cellulose foil and thetransparent paper known as'glassine, the following table of physicalproperties is given.

The cellulose acetate foil used as projection strips in accordance withthis invention may be r of suitable thickness, say on the order of0.001.

The strips of cellulose acetate foil that may be used for projecting maybe of any suitable width in accordance with the desired purpose. Suchstrips may have the width .of ordinary stock quotation ticker tape, orthey may be considerably wider whereby news or other information may beprinted thereon to be projected on a screen. When used in newspapersheet form, the ink on the strip is preferably dried in a warmatmosphere prior to projection. Such printed sheets of foil are quitepermanent in character, due to the fact that our ink, although it keepsmoist for a long time on the inking pad, can be dried after printing byusing warm air, making thereby a permanent record for projectionpurposes. There can therefore .be produced by our invention, wide sheetsof foil with characters Parts by weight Dye (such as Methyl Violet) 18Triacetin 41 Mixture of orthoand para-ethyl toluene sulfonamid 41 Thedye is ground in the triacetin and ethyl toluene sulfonamid. Othersuitable coloring materials may be used instead of the Methyl Violet.The triacetin and ethyl toluene sulfonamid may be replaced in whole orin part by other cellulose acetate plasticizers such a dim-ethylphthalate, dibutyl tartrate or monomethyl xylene sulfonamid. We havealso found that high boiling solvents such as glycol diacetate (b. p.186 C.) or benzyl alcohol (b. p. 206 C.),

in amounts of say 5 to parts by weight, mayv be added to the aboveformula to regulate the rate of drying. The principle of the inventionwith respect to our ink is to employ an agent or liquid that exerts asolvent action on the cellulose acetate or other organic derivative ofcellulose in the foil.

Our ink or marking fluid is superior to the ordinary glycerin-e ink notonly when used for marking cellulose acetate foil but when used inconnection with reconstituted cellulose foil or glazed paper, since itis not as hygroscopic as glycerine ink and is readily absorbed by glazedpaper or reconstituted cellulose foil.

It is to be understood that the foregoing detailed description is givenmerely by way of illustration and that many variations may be madetherein without departing from the spirit of our invention.

Having described our invention, what we desire to secure by LettersPatent is:

1. A printing ink adapted to be used for printin on transparent stripsconsisting of a. coloring material dispersed in a liquid consisting of aV non-hygroscopic solvent plasticizer for derivatives of celluloseselected from the group consisting of triacetin, ethyl toluenesulphonamides, dimethyl phthalate, dibutyl tartrate and monomethylxylene sulphonamide.

2. A marking fluid consisting of a dyestuff dispersed in a liquidconsisting of triacetin and ethyl toluene sulfonamide.

3. A liquid ink consisting of a coloring agent dissolved in dibutyltartrate substantially free from cellulose derivatives. 7

4. A liquid ink comprising a coloring agent dissolved in dibutyltartrate substantially free from cellulose derivatives.

MILLARD DEMAREST. KIRTLAND FLYNN.

